Philippine officials made the proposal Wednesday at the start of a three-day maritime forum in Manila organized by the Association of Southeast Asian Nations. Indonesia made a similar proposal at the conference, which was attended mostly by senior diplomats and private maritime experts.

The annual conference, now in its third year, is among efforts by ASEAN's 10 members to weld their diverse region of more than 500 million people into a European Union-like economic, political and security bloc by 2015 as a counterweight to Asian powerhouses like China.

Organizers were careful to point out that proposals like the offshore information-sharing system were not aimed at China, which some governments have accused of bullying smaller countries and aggressively asserting its territorial claims in the South China Sea.

“This forum is a platform for regional cooperation,” said Philippine Foreign Undersecretary Linda Basilio, who led the Manila conference. She said the South China Sea disputes were off the agenda.

ASEAN, founded in 1967, decides by consensus, meaning even one member can effectively block a proposal. China does not belong to the bloc, but some ASEAN members, including its current chairman, Cambodia, have close ties with Beijing.

Tensions have flared recently over territorial disputes in the region, including rival claims by China, the Philippines and Vietnam to South China Sea islands and waters that are believed to be rich in gas and oil and straddle busy shipping routes.

Two other ASEAN members — Brunei and Malaysia — also have been embroiled in South China Sea territorial rifts.

China has opposed any attempt to bring the disputes to international forums, including ASEAN, preferring to negotiate one-on-one with rival claimants. It has warned the United States, which has been reasserting its role as an Asia-Pacific power, to stay away from the sea disputes.

Despite the focus on regional cooperation, Vietnam's delegation briefly touched on the territorial disputes in Wednesday's conference, reiterating its adherence to a peaceful settlement of the conflicting claims.

The Philippine proposal says robust information sharing in the region will allow each country to better deal and respond to cross-border threats which would be difficult to monitor alone.

“These maritime security concerns are increasingly trans-boundary and multi-dimensional in nature,” the proposal said. “It would not be possible for one nation to single-handedly address some of these maritime challenges.”

ASEAN can tap existing information-sharing arrangements in the region, such as those dealing with sea accidents, piracy, and joint border patrols by some countries, to create an information-sharing system that adheres to international laws, according to the proposal.